Research

We build quantum devices coupling graphene quantum Hall edge modes to superconductors. In strong magnetic fields, Landau quantization produces chiral edges, while interactions near charge neutrality can stabilize a quantum Hall topological insulator with helical modes. Superconducting proximity induces phase-coherent Andreev bound states inheriting edge chirality or helicity. Using nanometre-scale gates, we define constrictions, Josephson junctions, and interferometers, tuning filling factor, edge separation, and spin polarization. DC transport and phase-sensitive interference probe coherence, mode selectivity, and interaction scales, establishing controlled benchmarks for topological superconductivity in graphene hybrids.

We study how strong disorder reshapes superconductivity and drives the superconductor–insulator transition. Using ultrathin films such as granular Al, InOx, and TiN, we probe electronic pairing, phase coherence, and dissipation from the nanoscale to gigahertz frequencies as disorder or magnetic field is tuned. Microscopy reveals patchy superconductivity, while transport and magnetometry expose glassy vortex dynamics and localized Cooper pairs. Microwave measurements quantify superfluid stiffness and intrinsic loss, establishing a unified, testable picture of the SIT and practical coherence benchmarks for quantum-circuit materials.